Virtualization storage technology makes storage resource become a huge “storage pool” by separating the logic image of the storage resource from the physical storage, and establishes one or more virtual volume(s) of different sizes depending on specific requirements in the storage pool. These virtual volumes are dynamically allocated to various application servers over a storage network. In this way, full use of the storage capacity can be made, and centralized management of the storage and reduction of the storage cost can be achieved, accommodating quickly increasing enterprise data storage needs.
With the development of cloud computation technology, cloud storage has also developed rapidly. A storage layer of a cloud storage is an integrated solution that is implemented based on storage virtualization technology in combination with various storage devices. In cloud storage, storage devices constitute an actual, physical storage network. Storage virtualization adds a virtual layer between a physical storage system and a server to manage and control the storage devices and to provide an online data storage service to the server. Changes in storage hardware are completely transparent to the server. Major manufacturers have provided different kinds of cloud storage schemes by which service providers can provide online data storage services to enterprise end users, and the users can request corresponding storage resources from servers according to their own requirements. Cloud storage thus brings more flexibility and scalability to users.